518 M. Roscnsthiehl on Monochlorinated Sulphuric Acid. 



A small glass bulb containing chloride of silicon was placed in 

 water containing some ammonia, and the bulb broken. After 

 the decomposition, the liquid was still feebly alkaline ; it was 

 allowed to stand for some days, then heated to boiling, filtered, 

 and the silicic acid well washed out. The chlorine was precipi- 

 tated from the filtrate by adding solution of nitrate of silver 

 acidulated with nitric acid, and the chloride of silver washed out 

 with water containing niti'ic acid. In two determinations 0'6738 

 and 1 '3092 grm. of chloride of silicon gave respectively 2*277 

 and 4*418 of chloride of silver, from which is obtained the average 

 28*01 as the equivalent of silicon. The same number also fol- 

 lows from the vapour-density of chloride of silicon (5*39) and 

 of fluoride of silicon (3*57), inasmuch as only the formulae SiCl* 

 and SiF 4 correspond to the vapour-density. Hence silicon, like 

 tin and titanium, is quadratomic. 



M. Roscnsthiehl* has investigated the action of anhydrous 

 sulphuric acid upon common salt. To a quantity of the former 

 substance, placed in a stoppered retort, a quantity of powdered 

 fused chloride of sodium was added. As the anhydrous acid 

 generally contained a trace of the hydrated acid, sufficient heat 

 was disengaged by the reaction thereby set up to melt the 

 anhydrous acid. When the first reaction was over, the mix- 

 ture was distilled until the residue fused. The distillate was 

 analysed, and was found to be monochlorinated sulphuric acid 

 formed in virtue of the reaction, 



NaCl + 2S 2 6 = Na02S0 3 + S 2 5 C1 



Anhydrous Bisulphate Monochlorinated 



sulphuric acid. of soda. sulphuric acid. 



A determination of the vapour-density confirmed the accuracy of 

 this formula. 



The new body is an oily colourless liquid of the spec. grav. 

 1*762, boiling between 145° and 150°, fuming in the air rather 

 less than anhydrous sulphuric acid. 



Projected upon a crystal of chromate of potash, it forms 

 immediately chloride of chromyle, 



KO CrO 3 + S 2 O 5 CI = KO S 2 O 6 + CrO 2 CI. 

 It acts in the cold on anhydrous acetate of soda without carbon- 

 izing it, and forms chloride of acetyle. This proves that it is a 

 good chlorinizing agent •. and as it is easily prepared, it may 

 sometimes replace chloride of phosphorus, over which it has the 

 advantage of not disengaging noxious vapours. 



Wilson has described f a method for determining the hardness 



* Comptes Rendus, October 7, 1861. 

 t Licbig's Annakn, September 18G1. 



